This graphic illustrates the different methods apps use to listen out for secret audio signals

MOST READ IN TECH AND SCIENCE

stalker's paradise

Tinder's creepy new update shares your EXACT location with everyone

lights out

Samsung will 'turn off' millions of TV sets across the UK this weekend

WATCH IT

New YouTube update leaves users FURIOUS – 'nobody asked for this'

WAITING GAME

Sony just teased the PS5 release date, and it's really bad news

ROMANTIC SPARK

Sophia the robot's creator says humans will MARRY droids by 2045

New Nokia

Nokia 6 2018: Where you can buy the updated smartphone

When the app hears this signal, it begins collecting information.

Companies can then track people’s location and work out what they are watching on television.

Apps that use the software can “precisely link the watching of even sensitive content such as adult movies or political documentations to a single individual – even at varying locations,” a team of German academics revealed earlier this month.

That means “advertisers can deduce what and how long an individual is watching and obtain a detailed user profile to deliver highly customised advertisements”.

The McDonald’s and Krispy Kreme apps were used in the Philippines.

It’s not known how common the technology was in European and UK apps.

We pay for your stories! Do you have a story for The Sun Online news team? Email us at tips@the-sun.co.uk or call 0207 782 4368